Originally Posted by chriskav73
A kind of long route to a short question for Parasound Halo amp owners/dealers:
The little bit of reading I did on electronics ('The Art of Electronics', Horowitz & Hill, 1989) explained in easy terms how to create low-noise, high quality devices, which oddly enough seem to be the same principles that JC used for the Halo amps. Based on the reading in the book, the interview with JC readily found on the web (http://www.parasound.com/pdfs/JCinterview.pdf
), and some sleepless nights reading about circuit topology/design on various forums (diyaudio, AVS, audioholics), it appears that Class A can help reduce listener fatigue by making the sound more musical (less odd order harmonics). When I e-mailed the support folks at Parasound regarding the Class A biasing of the A21 & A23, they responded that the A21 was roughly 2W/ch and the A23 was roughly 1W/ch Class A biased (kudos to Tom DeFiglio for such a quick response too). That would make sense to me as the latter has half the power of the former.
However, on the diyaudio.com site, John Curl made the comment that only the A21 or JC-1 monoblocks should be considered for serious listening. He made inference to the A23 being a cheaper version of the A21 that uses his design but not his direct input.
Not having an authorized Halo dealer nearby that has both the A21 & A23 to audition side-by-side, I have to resort to asking for opinions on the forum for my buying decision. Has anyone heard a difference in sound quality between the two at lower listening levels (i.e. where the extra headroom of the A21 is not a factor)? Thanks in advance for any opinions/advice, and thanks to pal1982 for starting this thread.
FWIW, I am looking to buy one of these amps (A21 or A23) for my main room (about 18'x15') to drive PSB Imagine T mains (~88/90db SPL/1W@1M; 4ohm nominal & minimum impedance) full range (no subwoofer used), using pre-outs from a Marantz SR5003. Half HT, half music (classical, jazz).